Microelectronic devices generally have a die (i.e., a chip) that includes integrated circuitry with a high density of very small components. In a typical process, a large number of dies are manufactured on a single wafer using many different processes that may be repeated at various stages (e.g., implanting, doping, photolithography, chemical vapor deposition, plasma vapor deposition, plating, planarizing, and etching). The dies typically include an array of very small bond-pads electrically coupled to the integrated circuitry. The bond-pads are external electrical contacts through which the supply voltage, signals, etc., are transmitted to and from the integrated circuitry. After forming the dies, the wafer is thinned by backgrinding, and then the dies are separated from one another (i.e., singulated) by dicing the wafer. Next, the dies are “packaged” to couple the bond-pads to a larger array of electrical terminals that can be more easily coupled to the various power supply lines, signal lines, and ground lines. Conventional processes for packaging dies include electrically coupling the bond-pads on the dies to an array of leads, ball-pads, or other types of electrical terminals, and then encapsulating the dies to protect them from environmental factors (e.g., moisture, particulates, static electricity, and physical impact).
FIG. 1 illustrates an existing microelectronic device package 10. The package 10 includes a microelectronic device 12 having a first end 21 and a second end 23, a lead frame 15 supporting the microelectronic device 12, and a packaging material 24 (shown in phantom lines for clarity) encapsulating the lead frame 15 and the microelectronic device 12. The microelectronic device 12 includes bond pads 14 positioned toward the second end 23. The lead frame 15 includes first lead fingers 16 that extend under the microelectronic device 12 from the first end 21 toward the second end 23. The lead frame 15 also includes second lead fingers 18 positioned toward the second end 23 of the microelectronic device 12. The bond pads 14 are grouped into three sets of bond pads 14a-c. First and third sets of bond pads 14a, 14c are electrically connected to the second lead fingers 18 with corresponding first and third wirebonds 20a, 20c, and the second set of bond pads 14b is electrically connected to the first lead fingers 16 with second wirebonds 20b. 
During assembly, the microelectronic device 12 is disposed on the first lead fingers 16. The bond pads 14a-c are connected to the first and second lead fingers 16, 18 using the wirebonds 20a-c. The first and second lead fingers 16, 18 together with the microelectronic device 12 are then disposed in a molding cavity. Liquefied packaging material 24 is injected into the molding cavity to encapsulate the microelectronic device 12 and the first and second lead fingers 16, 18.
One drawback associated with the microelectronic device package 10 is that the first lead fingers 16 and/or the second lead fingers 18 can shift during handling, transporting, assembling, or other processes. The first lead fingers 16 are especially prone to shifting because the first lead fingers 16 typically span almost the entire length L of the package 10. A small shift in neighboring first lead fingers 16 can cause the microelectronic device 12 to short circuit.
Another drawback associated with the microelectronic device package 10 is that the co-planarity of the first and second lead fingers 16, 18 cannot always be maintained during assembly. For example, the first lead fingers 16 can move out of the plane of FIG. 1 before or during the molding process so as to be offset from the second lead fingers 18. Further, the weight of the microelectronic device 12 can also cause the first lead fingers 16 to tilt or depress relative to the second lead fingers 18. If the first lead fingers 16 are not located in the proper plane, the encapsulation process may not properly encapsulate the entire package 10.
One conventional approach for reducing lead finger shifting is to secure the first lead fingers 16 and/or the second lead fingers 18 with adhesive tape. As illustrated in FIG. 1, adhesive tape strips 22a-c can be attached to the back sides of the first lead fingers 16 to prevent the first lead fingers 16 from moving. However, incorporating the adhesive tape strips 22a-c in the microelectronic device package 10 can reduce its reliability. For example, the adhesive tape strips 22a-c can absorb moisture, which can cause circuit failure in the microelectronic device 12. The adhesive tape strips 22a-c can also have different thermal expansion characteristics than other components of the microelectronic device package 10, which can cause cracking during operation. Accordingly, there is a need to provide more reliable and/or more robust packaging techniques.